Welcome! I think eBay may be your best bet to get one in a reasonable amount of time. eBay's traffic, even for HP-41's, is infinitely greater than what we get here (although you can't discuss, collect info, develop programs, etc. on eBay like you can here). A new splash on the market has been the Swiss Micros DM-41 which is somewhat less capable but a little faster, less expensive, and is being made today. Its appearance is more like that of the HP-12c, -15c, and -16c. It does not have the interfacing benefit of HP-IL, but do look into whether it has the ROM images of lots of modules built in. I don't know much about it except to know that a newcomer may find it worthwhile to look into. I'm quite sure it will handle synthetic programming, and it might handle assembly-language programming too.

I had posted under Buy & Sell that I have an HP-41CV for sale. It has the Surveying and Games modules with it, and is in very good condition. There are all manuals, a soft case, and original box, too. I want to get $250 for all and would pay to ship in the USA. I had engraved my SSN in the calculator, which I would obliterate before selling. Please reply if you are interested and I can give you any more info you might want.